This invention relates to a sensor for welding operations and more particularly to a multifunction feedback control sensor for gas-tungsten and gas-metal arc welding operations.
Automated welding requires a welding system capable of adapting to changing conditions encountered during the welding process. Many sensor systems have been developed to give automated welding systems the capability to adapt to variations in one parameter. For example, Agapakis, J. E., et al. Welding Journal vol. 65, No. 11, pp. 33-41 (1986), describes laser striping for joint tracking, and Hanright, J., Welding Journal vol. 65, No. 11, pp. 19-24 (1986), discusses through-the-arc sensing techniques. Additionally, coaxial viewing of the weld pool and infrared sensings are discussed in Richardson, R. W., et al., Welding Journal vol. 63, No. 3, pp. 43-50 (1984), and Lukens, W. E. , et al. , Welding Journal vol. 61, No. 1, pp. 27-33 (1982), respectively.
However, frequently it is desired to continuously monitor, in real-time, more than one parameter in the welding process, such as, the weld pool position and width, sensor-to-work piece distance and weld pool bead centerline cooling rate. Continuous monitoring of surfaces requires that light be reflected or emitted from those surfaces at sufficient strength so that attributes of the surface can be detected by the imaging device. Additional light, other than that which is required for imaging, shows up in the image as noise and degrades the quality of the image. In some cases, image degradation is so severe that the desired details or attributes within the image are lost and cannot be recovered. In the case of welding, the arc is a high luminosity light source that degrades the weld pool image to the extent that attributes of the weld pool and adjacent areas are unclear, unless light suppression techniques are used.
It is an object of this invention to provide an automated multifunction feedback control sensor for welding that is independent of significant operator interaction.
It is another object of this invention to provide a multifunction feedback control sensor capable of measuring weld pool position and width, sensor-to-work piece distance and weld bead centerline cooling rate.
Additional objects, advantages and novel features of the invention will become apparent to those skilled in the art upon examination of the following and by practice of the invention.